The United States and Japan will step up their defence cooperation to deal with the threat from nuclear-armed North Korea as tensions in East Asia remain high, officials from the two allies said on Thursday.

Ireland was the first country to ban smoking in all workplaces in 2008, four years after it criminalised smoking in pubs and restaurants.

This week the Irish government went a step further, announcing it would introduce plain packaging laws, a move Australia's health minister has welcomed.

"I'll be ringing the Irish health minister to congratulate him on this important move," Ms Plibersek told reporters in Sydney on Friday.

However, since the Australian laws came into effect in December last year, tobacco companies have launched a challenge with the World Trade Organisation.

Ms Plibersek said this should not deter Ireland from pursuing policy that would improve the health of its citizens.

"The fact that big tobacco is throwing so much money at trying to overturn Australia's plain-packaging legislation shows that it will work, that they know it will work," she said.

The minister also used World Tobacco Day to question whether the coalition supports anti-smoking measures, given the Liberal and National parties have accepted $1.97 million in donations from tobacco companies since 2004.

"If you're taking donations from big tobacco, it really brings into question of whether you're going to fight for the right to legislate to protect the health of Australians," she said.